Defective cobalt and copper tungstates mixtures with TiO2 for photocatalytic CO2 reduction

Abstract

In this work, the application of highly defective cobalt and copper tungstates was proposed for photocatalytic CO2 reduction. The materials were synthesized by hydrothermal method and characterized with SEM, EDS, XRD, XPS and DRS techniques. Studied materials were examined in photocatalytic CO2 reduction to CO in the gas phase, as bare photocatalysts and in mixtures with TiO2. The behavior of the junctions between the mixture components was determined using photoelectrochemical, spectroelectrochemical and surface photovoltage measurements. These studies reveal different types of junctions for the synthesized materials (disturbed S-scheme for CoT/TiO2 and type-I for CuT/TiO2). It was found the CuT/TiO2 mixture is more effective than CoT/TiO2 due to lower recombination rates of photogenerated charge carriers and the presence of a larger number of W5+ and Cu2+ active centers.

Keywords

• Tungstates
• Photocatalysis
• CO2 reduction
• Titanium dioxide
• Defects